Spin On Insulationg Layers

Spin On Insulationg Layers

      Integrated circuit technology uses deep trenches in silicon to
isolate circuits (Fig. 1).  Insulating material 1 is deposited into
the trenches 2 to form barrier layers and planarize the topography.

      Currently, polymers such as polyimide are used.  The use of
colloid and polysiloxane or colloid and polysilane mixtures in
suitable solvents could also be used as barrier layers because of
their good thermal stability, planarization and dielectric
properties.

      The colloid should consist of a material which enhances the
thermal stability of the polymer, e.g., a material which contains
colloidal silica together with components polysiloxane polyether and
partially hydrolysed silanols. Other mixtures may include colloids,
such as titanium dioxide, or any metal oxides, such as iron oxide,
used as the reinforcing agents and a polysiloxane or polysilane
together with suitable solvents.

      The advantages of such systems are that the colloid produces
enhanced thermal stability of the polysiloxane and improves
mechanical stability.

      The use of these, and other similar materials, allows the
placing of new metallurgies atop this planarizing/insulating layer
since the temperature at which these metals can be deposited is no
longer limited to 400oC as it is for polyimide coatings.  In
addition, the excellent coating and gap filling properties of these
materials is suitable for use in circuit layouts that use trench...